After a mysterious accident, a young high school student wakes up to discover he is caught in some kind of violent afterlife where a strange and avenging Angel is pursuing him. Confused and afraid, he joins a band of gun-toting teens intent on destroying the Angel and taking their destinies into their own hands

With the aid of a new member, the genius hacker, “Christ”, Yuri and the Battlefront decide to break into Angel’s lair and steal secrets from her hard drive. To distract the NPCs, they use the girl group Gldemo. But when the teachers interfere, the lead singer suffers a shocking fate.

With the lead singer of Gldemo now obliterated, a replacement must be found. The manic, high-strung Yui tries desperately to assume the role. Hinata, meanwhile, seeks to avenge a mistake made long ago on the baseball field by assembling the strongest team possible to defeat the other teams in the school. Otonashi worries the game could strike Hinata out in more ways than one.

To strip Angel of her scholastic power, Yui devises a plan for the Battlefront to replace Angel’s test results with bogus ones. She will be shamed, stripped of her title of Student Body President, and be out of their way for good. But they never realize the one who replaces her may be even more sinister than Angel could ever be.

Otonashi decides that the high-strung singer, Yui, needs to be pushed into finding peace and “moving on." To do so, he enlists Angel who shows him her new weapon: the dark and evil-looking Hand Sonic 5. But Yui has other plans—namely to beat the boys of Battlefront in a violent game on the soccer field.

As Hinata and Otonashi talk with Naoi, something strange happens: his shadow takes an enormous, evil form and engulf him. Weapons are powerless to stop the creature. Making matters worse, the Shadow monsters are multiplying and taking control of the members of Battlefront and the NPCs.

Set between episodes four and five, Yuri comes up with 'Operation High Tension Syndrome', encouraging the other members to behave as wildly as possible, so they would appear to be enjoying school without disappearing. Yuri hopes this will make Angel wonder what's happening and lead them straight to God.